Category Archives: Anemones and Jellyfish

I should be at home, cracking on with some work, but I’ve heard there are comb jellies about and I could do with some photos for my jellyfish course for ERCCIS.

Any excuse.

I cut through overgrown vegetation, down the cliff path to a favourite cove. In the ten minutes it’s taken me to walk here, the grey clouds have lifted and the sea’s looking good enough to dive into.

My progress through the rocky gully is slow. The warm weather has brought an explosion of slippery sea lettuce which blocks my view of my feet as they feel for underwater rocks. Tangles of pink spaghetti, the eggs of sea hares, are wrapped around many of the green fronds and a close inspection reveals that dozens of stalked jellyfish (Haliclystus octoradiatus) have already made their homes here.

As I move into deeper water, something catches my eye, floating below the surface. It’s so transparent it’s barely there, but it shimmers intermittently. With some difficulty, the current swishing the jelly back and forth, I scoop it up and carry it in cupped hands to a sheltered overhang. For a moment I think I’ve dropped it, then it swims out.

Barely there – a transparent Beroe cucumis comb jelly in my hand

I’m treated to a fabulous display of iridescence as the comb jelly beats its tiny combs, sending a trail of light and colour up the lines on its tiny body.

Between the current washing into the pool and the jelly’s own surprisingly speedy swimming efforts, it slips away each time I come close to getting it under the camera. To add to the fun, my camera can’t see it. I take a whole series of photos of nothing. The perfect transparency of the animal means I can only focus on the seaweed below.

The Beroe cucumis comb jelly has a characteristic sack shape.

When another comb jelly washes into the pool, I’m sure there will be lots more opportunities to attempt photos. Stepping out into the open water, I take some time to accustom my eyes, staring past the surface reflection into the water. Soon, I notice comb jellies everywhere.

The irridescent combs of Beroe cucumis

There are dozens, hundreds even, and some are large enough to fill the palm of my hand. Even the large jellies pose a challenge to my camera, but amongst the many seaweed shots, I start to take a few that show off the jellies’ light display.

While most are the large species, Beroe cucumis, with their characteristic sack shape, there are a few smaller ones amongst them. These are sea gooseberries, Pleurobrachia pileus. They are barely a couple of centimetres long, spherical, with two trailing tentacles.

A sea gooseberry with trailing tentacles. Its combs are arranged in lines up its sides.

Despite their tiny size, they are just as mesmerising as the B. Cucumis, the lines down their sides flickering every colour of the rainbow.

Sparkles of irridescence from a passing Sea gooseberry

Among all the comb jellies I spot an even smaller interloper, a hydroid medusa. Hydroids are related to jellyfish, but their adult form usually lives attached to seaweeds, stones or shells. This minute creature is a baby hydroid, looking very much like a jellyfish as it actively swims past, beating its bell fringed with short tentacles.

Hydroid medusa – probably Clytia hemisphaerica swimming by

The pattern of the cross on top of it and the fringe of dark spots around the edge of the bell suggest that it is a young Clytia hemispherica.

Hydroid medusa showing its delicate pattern and short tentacles.

The glare of sunlight on my screen combined with the transparency of all the animals I’m trying to photograph make it impossible to tell how I am doing. I give up taking photos and simply enjoy the spectacle until the tide calls time and forces me back up the beach.

Comb jellies are supposed to phosphoresce, which would be amazing to see. I’m wondering if I can sneak in a little night time rockpooling this weekend. Although the jellies are here in huge numbers today, they may disappear as quickly as they arrived. I should be working, but some things are just too exciting.

Nights out tend to become a distant memory when you’re a parent. For the most part I don’t miss them. I have, however, been looking forward to Junior being old enough to join me for night time rock pooling. Towards the end of last year, we tried it for the first time and, although the conditions weren’t ideal, he’s been asking to go again ever since.

The best low tides always happen around the middle of the day, and the middle of the night, but we compromise for this first family expedition of the year, choosing a reasonable low tide at around 10.30pm. The warm, calm weather provides good opportunities for seeing nocturnal activity and tonight I’m trying out my ultraviolet (UV) torch.

It doesn’t disappoint.

Head torch at the ready – night time rock pooling is a perfect adventure

I’ve always known that certain species glow under UV light, but I had no idea how much. We’ve barely taken ten paces out across the rocks when we see our first snakelocks anemone, shining from the darkness like an eerie green beacon. The colour is wonderfully alien.

Snakelocks anemone at night under UV light – a true alien of the Cornish rock pools

This fluorescence is caused by certain proteins within the animals that take in light of one colour and emit it as another. Some deeper water species can use these properties to appear red, even though red light is filtered out as it passes through the water, meaning the only light available to underwater creatures is UV or blue.

It’s not clear why snakelocks anemones and other sea creatures might want to fluoresce in this way. It seems there may be some benefit in it for their symbiotic algae or it might give them sun protection. It may just be a by-product of a protein that’s useful in other ways. Whatever the reasons, it produces an incredible glow. Junior is already talking of coming back at Halloween.

A spooky night-time rock pooling walk is definitely on the programme for this Halloweeen!

It’s not just the anemones that take our breath away. If you’re used to rock pooling in daylight when most animals are hiding away under rocks and seaweed, the sheer level of activity in after dark takes you by surprise.

A scratching, crackling sound stops us in our tracks. It’s coming from the rocks. I lift the seaweed to show Junior a group of limpets. Some are feeding, their strong radulas scouring seaweed off the rock and chipping bits of rock. Others are setting into their home scars, grinding their shells into their grooves to create a perfect fit. Close-up, their activities make a surprising amount of noise.

Limpets on their way home as the tide retreats

Most rockpool animals are largely nocturnal. Pools that seem empty in daytime become bustling cities of activity. We watch hermit crabs milling around in large numbers, crabs marauding through the pool and across the rocks, fish floating in plain sight. Prawns come towards the light and watch us before shooting away backwards.

A green shore crab looking blue in the UV lightHermit crabs are more active at night, every pool is teeming with them

Other Half spots a small species of spider crab (Macropodia sp.) decorated with long fronds of seaweed edging sideways across the pool. It’s moving too fast to take a clear photo in the poor light. The blurring makes it look even more alien.

A blurry small spider crab (Macropodia sp) moving across sand.

A scorpion fish lies still on the sand, watching out for prey.

A scorpion fish (Taurus bubalis) hiding in plain sight.

One surprise is the stunning colours of the seaweeds under the UV light. Some of the dark red seaweeds take on a far more intense, bright colour, glowing red, pink and orange. Where the top shells have worn spires, their tips glow pink.

A grey topshell on a red seaweed under UV light

After an hour, tiredness and cold begin to set in. We switch off our torches and take a moment to gaze at the stars before we head home to bed. Junior is already asking if we can come again the next night, and the next.

I’m not a fan of winter. Even though I go rock pooling all year round and love the way the wildlife varies with the seasons, the November to February period is a challenge for me. The thought of sticking my hands in icy-cold water makes me want to hibernate. Right on cue, a fierce northerly wind blows in for the spring tides. I layer up and wear my fluffiest, most comforting jumper to bring you this week’s blog post.

Obelia geniculata – a hydroid known as ‘Kelp fir’. Recognisable by its zig-zag ‘stems’.

I’m trying to photograph hydroids at the moment. These relatives of the jellyfish and anemones are generally translucent and no more than a few centimetres long, making them hard to spot. At this time of year when the seaweeds die back and the waves roll in, it’s especially tricky. My camera doesn’t like focussing on them and they won’t stay still in the current, but their nodding tentacles and curious structures are mesmerising.

Another hydroid – Coryne pusilla. This one can’t retract its tentacles into little cups. It has a ringed stem (visible in the bottom-left of the photo).

As always there are strange creatures galore. This Sea gherkin is unusually large and gnarled.

A Sea gherkin (Pawsonia saxicola) – this is a type of sea cucumber and clings onto the rock with its tentacle feet.

Among the sponges and brittle stars I come across this invasive species from the South Pacific, the Orange-tipped sea squirt, Corella eumyota.

The invasive Orange-tipped sea squirt

The twisted gut is very prominent in this species and you can see the orange colouration at the top. It’s thought this species may compete with native squirts and other invertebrates, but we will only find out by monitoring its spread. This is the first one I’ve recorded here.

Nearby I find the native sea squirt Ascidia mentula with lovely red flecks in its almost transparent test.

On the next tide we make a successful return visit to the beach where Cornish Rock Pools Junior achieved finding a world record haul of stalked jellyfish last year. We come close to matching the numbers we found last time. I lose count at 25 because Junior makes it clear he doesn’t want his record broken.

Many of the stalked jellyfish are juveniles, only a few millimetres long and it tests my eyes to pick them out among the swirling seaweed. Then I spot this 1mm pinprick of a jelly blob and take a photo in case it turns out to be a stalked jelly.

My eyes must still be good – a 1mm baby stalked jellyfish. It’s not possible to say for sure what species.

On my screen at home its column is clearly visible although the tentacles are either retracted or haven’t yet grown. Little is known about the very early stages of development of these creatures and how to separate the species by sight, but David Fenwick who runs the amazing Stauromedusae UK website confirms that it is definitely a stalked jelly.

Haliclystus octoradiatus – the blobs between the arms are primary tentacles, which easily identify this species from most others we see.

One of her sons does an impressive job of finding stalked jellies and even finds one that is in the middle of eating an amphipod. The current is too strong to get a great photo, but you can clearly see the unfortunate creature’s head sticking out of the stalked jellyfish’s mouth here.

A stalked jellyfish (Haliclystus octoradiatus) eating an amphipod.

I’ll be submitting all my stalked jellyfish records to help reinforce the evidence that will hopefully keep these protected species from harm.

A juvenile Calvadosia cruxmelitensis stalked jellyfish. We found 3 species of stalked jellyfish on the site.

I can’t help taking a look at some other things while I’m here. But before long the cold is hurting my fingers and chilling my insides in the sort of way that can only be fixed by a steaming mug of hot chocolate.

That’s the bit of winter I look forward to!

Rayed trough shellAslia lefevrei – the brown sea cucumber. This sea cucumber lives in crevices in the rock with just its dark tip poking out.Dysidea fragilis – or the hedgehog sponge as I call it.3-spot cowrie hanging on an overhang

We’re on a stomp about the beaches between Looe and Seaton, enjoying a patch of sunshine. “Watch out for Portuguese Man O’War jellies,” I warn Junior as we cross the muddy sand at Millendreath. I know there have been reports of them washing up all around the south west coast over the last few weeks, but there are none today. Inevitably, it’s something else that nearly gets me.

In a sandy pool at the sea’s edge, a flicker of movement catches my eye. It happens so quickly I can’t be sure there’s anything there but the sand is settling, suggesting something has just buried itself.

I call Junior over to look and I crouch low, reaching a hand to the water’s surface. If I can scoop the sand up from underneath I might be able to gently lift out the creature. Having seen plenty of well-camouflaged dragonets scooting about the pools today, I expect this to be another one. I stop short and stare into the shimmering pool.

Dragonets, especially the females, are perfectly camouflaged on sand.

It’s a good call. You never know what might be lurking in the rock pools. Near where I saw the movement is a sandy coloured lump. I think I recognise the shape, but it’s only when I lower my camera into the water and zoom right in that I can be sure. A Lesser weever-fish is staring down my lens, its frog-mouth gaping slightly, the rest of its body buried in the sand. Before I can take a shot it’s gone. Continue reading A close (enough) encounter with Weever fish.→

The Cornish summers are anything but predictable. One day I’m sweltering in shorts and beach shoes and the next I’m shivering in waders and a thick jumper. Although the showers are back with a vengeance, there’s always something to be found if I can make it across the rocks without breaking an ankle.

Painted top shell, East Looe

My first outing is to the rocks beyond East Looe beach and I’m pleased to come across a new colony of St Piran’s hermit crabs on the mid-shore.

A St Piran’s hermit crab starting to emerge from its shell.

They’re becoming a familiar sight around Cornwall and I’m starting to recognise them from the tips of their red legs, before their chequerboard eyes and equal-sized claws emerge from their shells. Continue reading Wrasse and wrack→

I doubt anyone in Looe can have missed it – the moment today when Cornish Rock Pools Junior found his first stalked jellyfish. His scream of, “I’ve actually found one!” rang across the beach and echoed off the hillside.

His first find was closely followed by his second, next to which was a third. A volunteer from Looe Marine Conservation Group found a fourth. The Natural England team found some more and by the time we were done we recorded a whopping 26 Stalked jellyfish.

Calvadosia campanulata stalked jellyfish

As all our records today were of two species (Calvadosia cruxmelitensis and Calvadosia campanulata) I’m feeling hopeful that they may soon be added as recognised features of the Looe and Whitsand Bay Marine Conservation Zone.

In December, good tides, mild temperatures and low winds coincide about as often as it snows on the Cornish coast (i.e. about once every ten years). Amazingly, today was one of those rare occasions and the rockpools were in impressive festive colours. What could be more Christmassy than this Dahlia anemone?

Festive colours in the Cornish rock pools – a Dahlia anemone

We were doing so well with our stalked jellyfish survey that I didn’t feel too bad about getting distracted. When I spotted a wriggling piece of seaweed, I chased it across the rocks.

If a piece of seaweed runs off, it’s probably a spider crab

As I suspected, under the seaweed decorations was a small spider crab species. This one was a Macropodia deflexa, a long-legged spider crab.

A Macropodia deflexa crab – covered in seaweed decorations

Relying on their camouflage, scorpion fish were lying still among the seaweed, allowing us to come right up to them.

A scorpion fish hides among the seaweed

It was a huge relief that everything turned out so well for our Stalked jellyfish survey. Had the conditions been less favourable we’d have been more likely to find none at all. 26 was an amazing total.

I needed my hot chocolate afterwards, but it was an afternoon well spent with some fabulous people. And tomorrow the forecast is even better… I’ll let you know what I find!

Another Christmas sea-flower – the Daisy anemone. In full bloom at Hannafore, LooeLike a string of Christmas lights – the Blue-rayed limpetOur Stalked jellyfish survey at Hannafore Beach, West Looe